Lithium cell with iron disulfide cathode

Abstract

A primary cell having an anode comprising lithium or lithium alloy and a cathode comprising iron disulfide (FeS 2 ) and carbon particles. The electrolyte comprises a lithium salt preferably lithium iodide (LiI) dissolved in an organic solvent mixture. The solvent mixture preferably comprises dioxolane and dimethoxyethane. The electrolyte typically contains between about 100 and 2000 parts by weight water per million parts by weight (ppm) electrolyte therein. The anode may be lithium metal or preferably is a lithium alloy. A cathode slurry is prepared comprising iron disulfide powder, carbon, binder, and a liquid solvent. The mixture is coated onto a conductive substrate and solvent evaporated leaving a dry cathode coating on the substrate. The anode and cathode can be spirally wound with separator therebetween and inserted into the cell casing with electrolyte then added.

1 . A primary electrochemical cell comprising a housing; a positive and a negative terminal; an anode comprising a lithium alloy; a cathode comprising iron disulfide (FeS 2 ) and conductive carbon, said cell further comprising an electrolyte inserted therein, said electrolyte comprising a lithium salt dissolved in a solvent mixture comprising dioxolane and dimethoxyethane, and wherein the water content in said electrolyte is between about 100 and 2000 parts by weight water per million parts by weight electrolyte. 
   
   
       2 . The cell of  claim 1  wherein the water content in said electrolyte is between about 200 and 1000 parts by weight water per million parts by weight electrolyte. 
   
   
       3 . The cell of  claim 1  wherein the water content in said electrolyte is between about 300 and 1000 parts by weight water per million parts by weight electrolyte. 
   
   
       4 . The cell of  claim 1  wherein the water content in said electrolyte is between about 300 and 450 parts by weight water per million parts by weight electrolyte. 
   
   
       5 . The cell of  claim 1  wherein said dioxolane comprises 1,3-dioxolane. 
   
   
       6 . The cell of  claim 1  wherein said dimethoxyethane comprises 1,2-dimethoxyethane. 
   
   
       7 . The cell of  claim 1  wherein said lithium salt comprises lithium iodide (LiI). 
   
   
       8 . The cell of  claim 1  wherein said lithium salt comprises a mixture of lithium iodide (LiI) and lithium trifluoromethane sulfonate (LiCF 3 SO 3 ). 
   
   
       9 . The cell of  claim 7  wherein said lithium iodide is dissolved in the solvent mixture in a concentration between about 0.3 and 1.4 moles per liter. 
   
   
       10 . The cell of  claim 1  wherein the weight ratio of dioxolane to dimethoxyethane is in a range between about 0.82 and 2.3. 
   
   
       11 . The cell of  claim 1  wherein said dioxolane comprises between about 50 and 90 percent by weight of said solvent mixture. 
   
   
       12 . The cell of  claim 1  wherein said solvent mixture further comprises between about 0.1 and 1 percent by weight 3,5-dimethylisoxazole. 
   
   
       13 . The cell of  claim 1  wherein said lithium alloy comprises lithium alloyed with at least one other component. 
   
   
       14 . The cell of  claim 13  wherein said other component is a metal or metalloid. 
   
   
       15 . The cell of  claim 14  wherein said metalloid is selected from the group consisting of silicon, germanium, and antimony, and mixtures thereof. 
   
   
       16 . The cell of  claim 13  wherein said other component may be an alkaline-earth element selected from the group consisting of barium and calcium, and mixtures thereof. 
   
   
       17 . The cell of  claim 13  wherein said other component is an elemental metal. 
   
   
       18 . The cell of  claim 13  wherein said other component comprises between about 0.05 and 5 percent by weight of said lithium alloy. 
   
   
       19 . The cell of  claim 17  wherein said elemental metal may comprise between about 0.1 and 5 percent by weight of said lithium alloy. 
   
   
       20 . The cell of  claim 17  wherein said elemental metal is aluminum. 
   
   
       21 . The cell of  claim 17  wherein said elemental metal is selected from the group consisting of magnesium, tin, indium, gallium, bismuth, and zinc, and mixtures thereof. 
   
   
       22 . The cell of  claim 1  wherein said anode and cathode are spirally wound with a separator sheet therebetween. 
   
   
       23 . The cell of  claim 1  wherein said cathode comprising iron disulfide (FeS 2 ) and conductive carbon is coated onto a substrate sheet comprising aluminum. 
   
   
       24 . A primary electrochemical cell comprising a housing; a positive and a negative terminal; an anode comprising a lithium alloy; a cathode comprising iron disulfide (FeS 2 ), and an electrolyte inserted therein, said lithium alloy comprises lithium alloyed with at least one other component selected from the group consisting of germanium, antimony, barium, indium, gallium, bismuth, zinc, and mixtures thereof. 
   
   
       25 . The cell of  claim 24  wherein said electrolyte comprises a lithium salt dissolved in a solvent mixture comprising dioxolane and dimethoxyethane. 
   
   
       26 . The cell of  claim 25  wherein said electrolyte has a water content between about 100 and 2000 parts by weight water per million parts by weight electrolyte. 
   
   
       27 . The cell of  claim 25  wherein said electrolyte has a water content between about 200 and 1000 parts by weight water per million parts by weight electrolyte. 
   
   
       28 . The cell of  claim 25  wherein said electrolyte has a water content between about 300 and 1000 parts by weight water per million parts by weight electrolyte. 
   
   
       29 . The cell of  claim 25  wherein said dioxolane comprises 1,3-dioxolane and said dimethoxyethane comprises 1,2-dimethoxyethane. 
   
   
       30 . The cell of  claim 25  wherein said lithium salt comprises lithium iodide (LiI). 
   
   
       31 . The cell of  claim 25  wherein said lithium salt comprises a mixture of lithium iodide (LiI) and lithium trifluoromethane sulfonate (LiCF 3 SO 3 ). 
   
   
       32 . The cell of  claim 30  wherein said lithium iodide is dissolved in the solvent mixture in a concentration between about 0.3 and 1.4 moles per liter. 
   
   
       33 . The cell of  claim 25  wherein said dioxolane comprises between about 50 and 90 percent by weight of said solvent mixture. 
   
   
       34 . The cell of  claim 24  wherein said other component comprises between about 0.05 and 5 percent by weight of said lithium alloy. 
   
   
       35 . The cell of  claim 24  wherein said cathode further comprises conductive carbon. 
   
   
       36 . The cell of  claim 24  wherein said anode and cathode are spirally wound with a separator therebetween.